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    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
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    <script>
      let obj = {};
      let s1 = Symbol("foo");

      Object.defineProperties(obj, {
        [s1]: { value: "qujun" },
        s2: { value: "hello" },
      });

      console.log(obj); /* {s2: "hello", Symbol(foo): "qujun"} */
      console.log(Object.getOwnPropertyNames(obj)); // ["s2"]
      console.log(Object.getOwnPropertySymbols(obj)) // [Symbol(foo)]
    </script>
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